History tells us that at least 15%, and possibly up to 33%, of cowboys in The Old West were African-American. Among them was William Pickett, who invented the trick we now call bull-dogging—catching and throwing a steer—though Bill’s habit of biting the cow’s lip to control it is no longer practiced. (Not too surprising, IMHO.)
Probably the most famous Black cowboy was Nat Love (below), aka Deadwood Dick, who wrote an autobiography of his years riding herd in a number of Western states. Love claims to have met many of the most famous Wild West figures, including Billy the Kid.

Nat Love (aka Deadwood Dick)
Ned Huddleston was known as The Calico Kid; he trained horses for the Wild Bunch and later became an outlaw himself, changing his name to Isom Dart.
On the other hand, Bass Reeves, who served as a scout and guide for the US Marshals in Arkansas and the Indian Territory (Oklahoma), was one of the first Black lawman; he became a Deputy US Marshall in 1875.
And lest we forget the women, Mary Fields, aka Stagecoach Mary, was the second woman and the first African-American woman to be hired as a mail carrier by the US Post Office. When the snow in Montana was too high for her coach and horses, 6-foot-tall Mary would deliver the mail on snowshoes.

Stagecoach Mary Fields